Catechism of the Catholic Church §2193 — excerpt
"On Sundays and other holy days of obligation the faithful are bound . . to abstain from those labors and business concerns which impede the worship to be rendered to God, the joy which is proper to the Lord's Day, or the proper relaxation of mind and body" (CIC, can.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.